Incorporating climate adaptation into landscape stewardship & restoration
Forest resiliency and warming temperatures
Hotter, drier summers, shrinking glaciers and the impacts of large wildfires in the Mt. Adams region have stimulated MARS to look at our work through a climate adaptation lens. While managing for forest resiliency has always been front and center, links between forest conditions and, in particular, water quantity, have more recently come into focus. Young, dense forests transpire over three times more water than older forests (HJ Andrews Experimental Forest) and therefore decrease stream flows in the summer when water is most critical. When wet season rains return, hydrophobic soils caused by stand replacing wildfires are incapable of absorbing and slowly releasing water. The net result: there are more pronounced and longer duration low and no flow periods during the summer; and more frequent and severe flooding in the fall, winter, and spring.
MARS manages forests with a keen eye to natural cycles, patterns and influences that have shaped our forests, watersheds and wildlife over time. On the Mt. Adams Community Forest, this includes longer harvest rotations, selecting suppressed trees that are at risk for pests and disease, and releasing larger trees to grow more vigorously. On partner lands, our management focus, that may emphasize something like wildlife habitat, incorporates similar strategies.
Small Gaps in the Forest
In addition to reducing stand densities, we are also creating small openings in the forest in pursuit of increasing water storage. The forest canopy intercepts snow when it is falling and then the snow sublimates or evaporates before reaching the ground. By creating small openings, or gaps, snow will be able to reach the forest floor. The gaps are also small enough that they are sheltered from snowmelt or evaporation from wind and sun. Thus, gaps are able to accumulate more snow that remains longer into the spring, supporting more consistent flow in Mt. Adams streams. While thinned stands also allow for more snow to reach the forest floor, heat radiated from trees melts the snow faster (UW Mountain Hydrology Research Group). But the net effect of reduced transpiration due to fewer stems is theoretically beneficial for water storage and release into headwater streams.
We utilize variable density thinning strategies – which includes thinning certain areas, creating gaps in others and leaving other areas completely alone. This type of management both increases the heterogeneity of our forests for better stand health, such as improved wildlife habitat and fire resiliency, while increasing water storage and creating a less “flashy” hydroperiod.
In recent years, MARS has developed an extensive monitoring program to help us identify if our projects are working as intended. In the winter of 2016/17, our monitoring showed that forest openings we created had 2x more snow (measured as Snow Water Equivalency) than thinned and untreated areas; and it persisted on average 10 days longer.
In the summer of 2017, we added meadow restoration to our portfolio of activities. Our first project took place in a wet meadow in the headwaters of Rattlesnake Creek, a major tributary to the White Salmon River. With the help and guidance of a private landowner, we felled trees into a small stream/wet meadow that had recently been fenced to exclude cattle. A degraded riparian area suffered from conifer encroachment, where desirable hardwood species were being shaded and outcompeted as a result. We were able to enhance a quaking aspen grove and simultaneously add wood to the stream; increasing channel complexity, reducing streambank erosion, and reconnecting the stream with its floodplain. We created our own version of Beaver Dam Analogs (BDA’s) by felling trees directly into the stream channel and using the downward facing branches as stakes. We then limbed the rest of the tree and added this material to the structures. The “Tree DA’s” are expected to slow down stream flow, decrease stormwater runoff and increase the availability of water to infiltrate and replenish groundwater.
Working with Conboy Lake National Wildlife Refuge, MARS also implemented our first “Plug and Pond” projects in two wet meadows in the headwaters of Outlet Creek, a tributary to the Klickitat River. Homestead era ditches created an incised channel disconnected from the floodplain, in this case, the adjoining meadow. We “plugged” old ditches with rootwads, logs, and branches; allowing the stream to “pond” in front of the structures and reconnect with the meadow. Students from the Glenwood School contributed by gathering cuttings from nearby sources of water-loving shrub and tree species, potting and nurturing them at school, and then planting the seedlings at the project site.
Every Drop Counts
Thanks to a major investment from the Wildlife Conservation Society’s Climate Adaptation Fund MARS was able to complete these climate-resiliency focused restoration activities across 1,200 acres of upland forest and 30 acres of riparian and wet meadow habitat during 2016 & 2017.
This may not seem like much in the bigger picture, but we believe that with every drop and continued collaboration, cooperation, and support both our communities and our natural systems will be better prepared for our changing climate.
Check out partners in the Mt. Adam’s region that are working on how to address large-scale landscape stressors such as climate change.
Southwest Washington Adaptation Partners